Cubic Millimeter High Resolution 3D Inner-Volume GRASE (IV-GRASE) CEST MRI Using T₁-Integrated Variable Density CAIPI...

Area of Science:

• Magnetic Resonance Imaging (MRI)
• Biomedical Engineering
• Quantitative Imaging

Background:

• Chemical Exchange Saturation Transfer (CEST) MRI offers valuable insights into tissue physiology.
• Current CEST MRI techniques often face challenges with efficiency, resolution, and quantitative accuracy.
• Simultaneous acquisition of T1-weighted and CEST data is desirable for comprehensive tissue characterization.

Purpose of the Study:

• To develop a novel cubic-millimeter, high-resolution Chemical Exchange Saturation Transfer (CEST) Magnetic Resonance Imaging (MRI) sequence.
• To enhance the efficiency and quantitative stability of CEST MRI.
• To enable simultaneous T1-weighted and CEST imaging in a single acquisition.

Main Methods:

• Developed a hybrid sequence combining inversion-recovery T1 and multi-offset CEST modules using inner-volume GRASE (IV-GRASE) readout.
• Improved acquisition efficiency with variable-density random-walk sampling.
• Employed a self-calibrated joint reconstruction framework with sparsity and low-rank constraints.

Main Results:

• Achieved simultaneous T1 and CEST imaging with reduced artifacts and improved quantitative stability.
• Demonstrated accurate T1 and Z-spectral measurements in phantoms with co-registered datasets.
• Preliminary patient studies revealed distinct tissue heterogeneity and exchange-dependent relaxation contrast.

Conclusions:

• The proposed hybrid T1-CEST MRI sequence offers efficient, artifact-reduced, and quantitatively reliable high-resolution imaging.
• This advancement facilitates the feasibility of quantitative CEST analysis in clinical settings.
• The sequence enables comprehensive tissue characterization in a single MRI acquisition.